At one fell swoop

Answer: Option A

Explanation:

Example : My brother is at sea in maths, he can not solve even the easy problems.

Answer: Option B

Explanation:

Example : It is the high time for the two brothers to bury the hatchet and mend their fences.

Answer: Option C

Explanation:

Example : The sole reason of his success is that he never throw up the sponge to the conditions.

Answer: Option A

Explanation:

Example : Days spent in my village were the halcyon days of my life.

Answer: Option C

Explanation:

Example : He is such a great spokesperson, whenever he takes the floor there is a pin drop silence.